“APSARA” – the celestial water nymph, by Pandit Nehru himself. The basic design for this reactor was frozen in July 1955 and Indian scientists and engineers completed the construction in just over a year.

• With APSARA, India became the first Asian country outside the erstwhile Soviet Union, to have designed and built its own nuclear reactor.
• The next crucial step involved the planning of larger reactors having much higher neutron flux and power than what was available at APSARA.
• This plan materialized in 1960 with the building of CIRUS, a high power (40 MWt) research reactor.
• This reactor, then known as the Canada India Reactor or CIR for short, was built in collaboration with Canada.
• In early 1961, a zero energy critical facility named ZERLINA (Zero Energy Reactor for Lattice Investigations and New Assemblies) was built, for studying various geometrical aspects (lattice parameters) of a reactor fuelled with natural uranium and moderated with heavy water.

Source: ForumIAS